| From 5a267832c2ec47b2dad0fdb291a96bb5b8869315 Mon Sep 17 00:00:00 2001 |
| From: Paul Burton <paul.burton@mips.com> |
| Date: Fri, 22 Jun 2018 10:55:45 -0700 |
| Subject: MIPS: Call dump_stack() from show_regs() |
| |
| From: Paul Burton <paul.burton@mips.com> |
| |
| commit 5a267832c2ec47b2dad0fdb291a96bb5b8869315 upstream. |
| |
| The generic nmi_cpu_backtrace() function calls show_regs() when a struct |
| pt_regs is available, and dump_stack() otherwise. If we were to make use |
| of the generic nmi_cpu_backtrace() with MIPS' current implementation of |
| show_regs() this would mean that we see only register data with no |
| accompanying stack information, in contrast with our current |
| implementation which calls dump_stack() regardless of whether register |
| state is available. |
| |
| In preparation for making use of the generic nmi_cpu_backtrace() to |
| implement arch_trigger_cpumask_backtrace(), have our implementation of |
| show_regs() call dump_stack() and drop the explicit dump_stack() call in |
| arch_dump_stack() which is invoked by arch_trigger_cpumask_backtrace(). |
| |
| This will allow the output we produce to remain the same after a later |
| patch switches to using nmi_cpu_backtrace(). It may mean that we produce |
| extra stack output in other uses of show_regs(), but this: |
| |
| 1) Seems harmless. |
| 2) Is good for consistency between arch_trigger_cpumask_backtrace() |
| and other users of show_regs(). |
| 3) Matches the behaviour of the ARM & PowerPC architectures. |
| |
| Marked for stable back to v4.9 as a prerequisite of the following patch |
| "MIPS: Call dump_stack() from show_regs()". |
| |
| Signed-off-by: Paul Burton <paul.burton@mips.com> |
| Patchwork: https://patchwork.linux-mips.org/patch/19596/ |
| Cc: James Hogan <jhogan@kernel.org> |
| Cc: Ralf Baechle <ralf@linux-mips.org> |
| Cc: Huacai Chen <chenhc@lemote.com> |
| Cc: linux-mips@linux-mips.org |
| Cc: stable@vger.kernel.org # v4.9+ |
| Signed-off-by: Huacai Chen <chenhc@lemote.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/mips/kernel/process.c | 4 ++-- |
| arch/mips/kernel/traps.c | 1 + |
| 2 files changed, 3 insertions(+), 2 deletions(-) |
| |
| --- a/arch/mips/kernel/process.c |
| +++ b/arch/mips/kernel/process.c |
| @@ -637,8 +637,8 @@ static void arch_dump_stack(void *info) |
| |
| if (regs) |
| show_regs(regs); |
| - |
| - dump_stack(); |
| + else |
| + dump_stack(); |
| } |
| |
| void arch_trigger_all_cpu_backtrace(bool include_self) |
| --- a/arch/mips/kernel/traps.c |
| +++ b/arch/mips/kernel/traps.c |
| @@ -344,6 +344,7 @@ static void __show_regs(const struct pt_ |
| void show_regs(struct pt_regs *regs) |
| { |
| __show_regs((struct pt_regs *)regs); |
| + dump_stack(); |
| } |
| |
| void show_registers(struct pt_regs *regs) |